DVD drive read error while disk is detected / mounted correctly

I installed Ubuntu Feisty Fawn from its LiveCD, and had no problem with it.
Then, booting from the hard drive, I discovered that I could not access my CDs (even the LiveCD I made the installation from).
Every file I try to access seems corrupted. Anyway : I can mount CDs and browse them correctly.

I tried multiple modifications of FSTAB related to charset, filesystem and mount point. No success in them.
I finally discovered that the only difference between LiveCD and hard drive installation is that the live CD considers the DVD drive as an IDE device, while the hard drive installation mounts it as a SCSI device. I understand that this is the correct way to make the burner functionality usable, but if this makes the CDs unreadable, I'd rather remove SCSI emulation, and use my DVD as readonly...
So : my question is : how can I remove SCSI emulation so that my hard drive installation behave like the LiveCD ?
Of course, if you find a way to ALSO burn CDs, I'm willing to listen :-)

I run the dmesg command and found the following lines, wich may be usefull to you (I admit that I do not understand that) :

Thank you. Anyway, as I told : I removed the DVD-burner and replaced it with a simple reader.
Moreover, this DVD burner has always worked correctly on Windows, on the same computer, using the same connector... I really doubt it is a hardware problem.